Carburetor



Aug. 21 1934. LE BRETON 1,971,293

CARBURETOR Filed June 6, 1932 .ZNVE'NTO A EON 5 BRz'To/v ATTORNEY Patented Aug". 21, 1934 ere . CARBURETOR L01l :[1 B1't0n, LS Lilas, France, assignor to Soc1ete a Responsabilite Limitee Carburateur Nutrix, Courbevoie, France Application June 6, 1932, Serial No. 615,723

- InFrance June 12, 1931 3 Claims. (01. 261-41) The present invention relates to a carburetor of the float-feed type, operating with submerged fuel-feeding outlet and comprising a progressive control by means of air.

It has for its object to maintain a constant ratio between the fuel and air, irrespectively of the speed of the vehicle.

In such apparatus, the output of the submerged fuel-feeding outlet depends upon the pressure of the air in the chamber supplied by the said fuelfeeding outlet, the tube admitting external air being directed towards the front. The fuel mixture becomes poorer in proportion to the speed of travel of the vehicle, and this may occasion ldback-flring, which is a cause of fire and will in all cases cause disturbances in the action.

In the case of a carburetor employed upon aircraft, when at a certain altitude, the weight of the air admitted becomes reduced, and thus the fuel mixture becomes richer, and hence the apparatus operates in a defective manner.

The carburetor, the subject-matter of the invention, is characterized by the fact:

1. The air necessary for the operation of the fisubmerged fuel-feeding outlet is supplied by a venturi which is situated according to the direction of travel of the airplane or the like, and in whose vacuum region is situated the orifice through which this air will enter the chamber supplied by the said fuel-feeding outlet;

2. The upper space in the float chamber above the level of the liquid communicates, through an adjustable needle-valve, with an orifice which is situated in the suction region of the venturi.

35. The following description, with reference to the accompanying drawing which is given by way of example, sets forth an embodiment of the invention.

The single figure shows a vertical section of a 0 form of construction of the carburetor.

The air for the fuel mixture enters through an orifice 1 into a tube 2 containing a diffuser 3 and a throttle 4, said orifice being situated next the front of the airplane or motor-vehicle; the tube ,2 communicates by its outer end with the engine.

The float chamber 5 is connected with the gasoline tank; it is provided with an atmospheric outlet 6, and contains a float '7. Said chamber is connected with the tube 2 by a closed U tube 0, whereof one branch 8a extends upwardly in the said chamber and above the level of the liquid, and the other branch 8b is located outside of the chamber and is connected with the diffuser by a small tube 9, and also with an orifice 10 pierced in the tube 2 at a point above the difiuser and serving as a slow-speed orifice. The throttle 4. partially closes this orifice 10 when it is in the closing position. The branch 8b is connected with the orifice 10 by a tube 11 which extends nearly to the bottom of the said branch.

The submerged fuel-feeding outlet consists of an orifice 12 formed in the branch 8a at a short distance from the bottom of the float chamber. A calibrated tube 13, whose open top is located somewhat below the top of the branch 8a, extends 5 entirely through this branch, and communicates at its lower end with the suction region of a venturi l l which is mounted, in the directon of travel of the aeroplane or the like, in a lower tube 15,

into which the air enters in the same direction 70.

as it enters the tube 2.

The upper part of the float chamber, above the level of the liquid, is connected with the suction region of the venturi by a tube 16, and the cornmunication between this tube and the float chamaforesaid output being inversely proportional to this pressure or amount of air. If the speed of the aeroplane (or the like) increases, the rate of flow of the air in the tube 2 and in the tube 15 also increases, and the suction also increases in the suction region of the venturi, and hence the amount of air entering the tube 13, and the pressure in the space 8a, will diminish in like manner, whereby the feed of the submerged fuel-feeding outlet will be increased. Hence the proportion between the air circulating in the diffuser 3 (whose amount has also increased) and the fuel, is thus maintained at a practically constant value.

With an apparatus of this construction, a small diffuser may be employed, and thus the multi-cylinder engines are enabled to start with facility, without prejudice to the maximum speed conditions.

It is not necessary to make use of a compressor, which is an apparatus having complicated parts subject to improper working.

In the case of an engine mounted on an airplane or the like upon reaching a certain altitude, the gas mixture becomes richer. By manually operating the needle-valve 17, the upper part of the float chamber is connected with the suction region of the venturi, thus reducing the pressure in the float chamber and hence the output of the submerged fuel-feeding outlet.

By regulating the said needle-valve, the ratio between the air and the fuel can be maintained at a practically constant value.

When the said carburetor serves to supply a stationary engine, it may be readily operated by the use of suitable mechanical means, such as a blower or the like.

Obviously, the said invention is not limited to the form of construction herein set forth, andis,

second venturi traversed by a current of air caused by the movement of the vehicle, and a second tube establishing communication with the zone of depression of said second venturi through the upper portion of the tube within the fuel chamber.

2. A carburetor according to claim 1 including an additional air pipe leading from the zone of depression of the second venturi and opening into the space in the fuel chamber above the combustible level therein, and means for regulating the passage of air through the air pipe.

3. A carburetor for a vehicle propelling internal combustion engine, said carburetor having a constant fuel level including a fuel chamber, a tube in said chamber and communicating therewith through a submerged spray, means communicating with the lower portion of the tube for delivering fuel from the chamber, a venturi traversed by a current of air caused by the movement of the vehicle, and a second tube establishing communication between the zone of depression of said venturi and the upper portion of the tube within the fuel chamber, whereby to control the feed of fuel through the spray.

LEON LE BRETON. 

